This invention relates generally to portable computers having one or more loudspeakers for emitting audible sound, and more particularly to a notebook computer loudspeaker configuration for improving audible sound quality at low frequencies.
A conventional notebook computer is approximately the size of a standard sheet of paper, (e.g., 21.6 cm by 27.9 cm; or in English units --8.5 inches by 11.0 inches). The thickness of such a notebook computer typically is 5.0 cm to 8.0 cm. In efforts to increase transportability and usability, the evolution has been toward smaller, lighter portable computers. The typical notebook computer includes a display screen housing hinged to a keyboard housing. The display screen housing folds down against the keyboard where the two housings latch together. A processor board, keyboard and disk drive often are mounted within the keyboard housing. Additional features include input/output ports and one or more compartments for receiving PC cards, (i.e., peripheral devices conforming to the Personal Computer Memory Card International Association (PCMCIA) standards for personal computer-based peripherals). In an effort to bring multimedia applications to the notebook computer, loudspeakers and sound cards also may be included.
A shortcoming of loudspeakers used with notebook computers is the generally inferior sound quality achieved relative to conventional stereophonic shelf-top speakers, or even, internal or external speakers used with desktop computers. One reason for the poorer sound quality is the relatively smaller speaker sizes. The smaller speaker size makes it difficult to produce quality sound over a wide frequency range, and particularly at lower frequencies. Coupled with the restricted speaker-box volume in which the loudspeaker is housed, quality sound at lower frequencies is difficult to achieve. Larger speaker-boxes provide space for accommodating given wavelengths of sound waves. Increasing the size of a notebook computer to accommodate significant speaker-box sizes is undesirable, however. Such inclusion would be a trade-off on the transportability of the computer. Accordingly, there is a need for a speaker configuration in a notebook computer which improves sound quality without increasing the size requirements of the computer housing.